Signs warn not to drink the lead-contaminated water from a water fountain in Flint, Mich.

This is not just a localized problem, it is rampant everywhere. More and more the quality of our water is being compromised and in turn our health and wellbeing gets compromised too.

Flint, Mich., isn't the only American city with a lead problem. Though the health crisis in Flint has highlighted the use of lead in water pipes, author David Rosner tells Fresh Air's Terry Gross that lead, which is a neurotoxin, can be found throughout the U.S. on walls, in soil and in the air.

"The problem with lead is that it's now really everywhere, and we've created a terribly toxic environment in all sorts of ways," he says.

Lead is particularly dangerous to young children. In their book, Lead Wars, Rosner and co-author Gerald Markowitz describe the ways in which even small exposures can interfere with a child's brain development and cause lasting learning challenges.

Rosner adds that even a small amount of lead can have a lasting effect on a child's health. "As early as the 1910s and 1920s, [doctors] were documenting children who had absorbed lead on their fingers as dust and had put their hands in their mouth and actually began going into convulsions," he says. "It's not like you need a lot of it."

Interview Highlights

On the pervasive use of lead in the first half of the 20th century

Gerald Markowitz: The average can of paint in the 1900s to around 1950 contained up to 50 percent of lead carbonate, which is lead. So it's a lot of lead, and it takes just a couple of grams of lead to send a kid into serious damage. So, what we did essentially for 50 years is cover our entire nation. During the period when the economy was moving from an agricultural society to an industrial society to an urban society, we built most of the structures that surround us even today ... in inner cities and poorer communities, and those were all being painted at one point or another, during that 50-year period, with lead. Our cities expanded dramatically, and with it went the covering of this society with lead paint.

On the use of lead in pipes

Markowitz: In Washington, D.C., just a few years ago there was a tremendous scandal about lead in the drinking water and lead even in the public schools. And one of the unfortunate things is that we do not have a testing program for lead in public schools in the water, so we don't really know how many children are being exposed to lead in the water in their schools. ...

David Rosner: Not all cities are using lead pipes. Some water systems actually use copper and iron and cement as their piping source. So it's often a problem in cities that were built between the early 1900s, late 1800s and the early 1940s, and in cities where cheaper housing sometimes exists, because lead is relatively cheap, and in which unions did not have any power to make sure that lead was not used in their pipes. In the early part of the century, for example, in New York City, we don't have as big a problem with lead in pipes, because many of the unions demanded that we use copper and essentially we, by happenstance, don't have that kind of problem.

On how people figured out that lead was toxic

Rosner: During the 1920s, researchers in the United States and in England and elsewhere began to really identify lead poisoning in children and they identified the toys and cribs and the woodwork as a source of lead, and they said, "We have a problem here, and the problem is that the child ... lives in a lead world. Everything around them by this point is covered with lead — their toys, their cribs, their playthings, their woodwork, the walls — everything has some lead in it."

And these kids who crawl on the floor are getting this dust on their hands, putting their hands in their mouth, and absorbing lead, and lead, we know, accumulates in the body and ... that's the problem. So by the 1920s the medical and public health community had essentially identified this major problem. The industry itself began a marketing campaign and the marketing campaign essentially tried to assuage the worries of the larger community about the dangers of lead. They started saying, "Lead in our pipes and lead on our walls and lead in our paint is not a health problem."